Learn about tick diseases in dogs.

Lyme disease isn’t the only disease dogs can contract from ticks. Ticks can also carry canine ehrlichiosis, canine anaplasmosis and Rocky Mountain spotted fever. These diseases are often mistaken for other conditions and cannot be accurately diagnosed without a trip to the vet. Tick bites on dogs are hard to detect, and tick disease signs may not appear for 7–21 days or longer after a tick bite, which makes regular screening a must.

Lyme disease
Canine ehrlichiosis
Canine anaplasmosis
Rocky Mountain spotted fever
Heartworm disease

Lyme Disease in Dogs

Lyme disease is caused by the bacterium Borrelia burgdorferi and is transmitted by the deer tick (often referred to as the black-legged tick). Signs of Lyme disease in dogs are difficult to detect, and warning signs may not appear until several months after infection. Signs may come and go and can mimic other conditions. Cases vary from mild to severe. In severe cases of Lyme disease, kidney failure can occur.

Most common signs of Lyme disease:

• Recurrent arthritis/lameness that lasts 3–4 days, sometimes accompanied by loss of appetite and depression
• Reluctance to move or a stiff, painful gait
• Swollen joints that are warm to the touch
• Pain in the legs or throughout the body
• Fever, fatigue and swollen lymph nodes

U.S. Regions Where Lyme Disease May Affect Your Dog

Lyme disease has been found throughout the United States, but infections are most frequently diagnosed in the northeastern, mid-Atlantic and north-central states, as well as in California.

Canine Ehrlichiosis [ ur-lik-ee-oh-sis ]

Canine ehrlichiosis is caused by the bacterium Ehrlichia. phagocytophila and is transmitted by the brown dog tick. Like Lyme disease in dogs, warning signs may not be readily apparent. If left untreated, the disease progresses to a symptom-free phase, which can last days, months or years.

Mild signs appear to mimic a vague illness, the most obvious sign of which is weight loss. Severe cases of canine ehrlichiosis that go undiagnosed and untreated can end in death.

Most common signs of canine ehrlichiosis:

• Fever
• Runny eyes and nose
• Loss of appetite
• Depression
• Weight loss
• Swollen lymph glands
• Eye disease
• Retinal bleeding
• Spontaneous nose bleeds
• Bruising (petechiae) on gums and belly
• Swelling of limbs

U.S. Regions Where Canine Ehrlichiosis May Affect Your Dog

Canine ehrlichiosis is found throughout the United States. The highest concentration of cases is reported in southwestern and Gulf Coast regions.

Canine Anaplasmosis [ an-uh-plaz-moh-sis ]

Sometimes referred to as dog fever, or dog tick fever, canine anaplasmosis is caused by the bacteria Anaplasma phagocytophilum or is transmitted by the deer tick (often referred to as the black-legged tick)—the same tick that transmits Lyme disease. Another form of Canine Anaplasmosis is caused by the Anaplasma platys bacterium carried by the brown dog tick. Although these two forms of Anaplasmosis present with different signs, both may pose a serious threat to your dog's health.

Most common signs of canine anaplasmosis:

• Arthritis-like stiffness with painful joints
• High fever accompanied by lethargy, loss of appetite, vomiting and diarrhea
• Neurological signs (infrequent) resulting in seizures and neck pain

U.S. Regions Where Canine Anaplasmosis May Affect Your Dog

Canine anaplasmosis is found throughout the United States, primarily in the northeastern, mid-Atlantic and north-central states, as well as in California.

Rocky Mountain Spotted Fever

Rocky Mountain spotted fever in dogs is caused by the bacterium Rickettsia rickettsii and transmitted by the American dog tick, the wood tick and the lone star tick. In most cases, Rocky Mountain spotted fever in dogs lasts about two weeks, but in severe cases it can result in death.

Most common signs of Rocky Mountain spotted fever:

• Fever
• Skin lesions
• Stiffness when walking
• Neurological abnormalities

U.S. Regions Where Rocky Mountain Spotted Fever May Affect Your Dog

Despite its name, Rocky Mountain spotted fever is prevalent throughout most of the United States, with the highest concentrations in the Rocky Mountain states, California and the Southeast.

Heartworm

Heartworm is transmitted by mosquitoes, not ticks. But as a serious and potentially fatal threat to dogs, it’s worth a mention here. Despite widespread awareness of the disease, it’s estimated that as many as half of all dog owners are not using heartworm preventatives. In early stages, heartworm has no visible signs, which is why preventive measures are so important. As the infection takes hold, more signs will emerge.

Most common signs of heartworm:

• Persistent cough
• Exercise intolerance
• Difficulty breathing/abnormal lung sounds
• Abnormal heart sounds
• Swelling of the abdomen

Note: The above signs indicate advanced infection, which often results in death.

U.S. Regions Where Heartworm May Affect Your Dog

Heartworm is found in all 50 states, with the highest number of reported cases in the South, Midwest and California.

For more information about heartworm, visit the Web site of the American Heartworm Society at www.heartwormsociety.org.